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Free keywords:
ACTIVATED ALKENES; 1,3-DICARBONYL COMPOUNDS; N-ARYLACRYLAMIDES; BOND
FORMATION; CARBOCYCLIZATION; SPIROOXINDOLES; ACRYLAMIDES;
1,2-ALKYLARYLATION; FUNCTIONALIZATION; DERIVATIVESChemistry; BrOnsted acid catalysis; radicals; cyclization; heterocycles; peroxides;
Abstract:
Oxindoles bearing ketone side chains in the 3-position can be synthesized by BrOnsted acid catalysis from N-aryl methacrylamides, ketones, and hydroperoxides. The cyclized products are presumably formed in a radical cascade reaction, initiated by decay of intermediate alkenyl peroxides. In the case of acrylic substrates that do not undergo cyclization, -peroxyketones were isolated instead, indicating that the final cyclization step of the cascade does not take place in these cases.
